US3935526A - DC-to-DC converter - Google Patents

DC-to-DC converter Download PDF

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Publication number
US3935526A
US3935526A US05/388,260 US38826073A US3935526A US 3935526 A US3935526 A US 3935526A US 38826073 A US38826073 A US 38826073A US 3935526 A US3935526 A US 3935526A
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US
United States
Prior art keywords
transformer
winding
converter
choke coil
voltage
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US05/388,260
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English (en)
Inventor
Yasuji Kamata
Kazuo Katou
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Hitachi Ltd
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Hitachi Ltd
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Publication date
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Publication of US3935526A publication Critical patent/US3935526A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of DC power input into DC power output
    • H02M3/22—Conversion of DC power input into DC power output with intermediate conversion into AC
    • H02M3/24—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters
    • H02M3/28—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC
    • H02M3/325—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33538—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only of the forward type
    • H02M3/33546—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only of the forward type with automatic control of the output voltage or current
    • H02M3/33553—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only of the forward type with automatic control of the output voltage or current with galvanic isolation between input and output of both the power stage and the feedback loop

Definitions

  • This invention relates to a DC-to-DC converter in which a voltage is derived from the secondary winding of a transformer by appropriately switching a DC voltage applied to the primary winding of the transformer and a DC output voltage proportional to the DC voltage applied to the primary winding can be obtained by rectifying and smoothing the derived voltage.
  • This type of DC-to-DC converter can enjoy stable operation and also serve as an excellent isolator.
  • the current through the primary winding of the transformer is unidirectional so that if the core used in the transformer exhibits a rectangular hysteresis characteristic the core is magnetically saturated in one direction. Consequently, the transformer can no longer perform its proper function and the DC-to-DC conversion operation will be imposssible. Therefore, some means must be provided to reset the core saturated in the one direction.
  • the switching element used in the converter is turned on and off very rapidly, it sometimes happens that when the switching element is turned off, flyback voltages are generated which may damage the element.
  • the most common is a reset winding provided on the magnetic core of the transformer, through which DC reset current from a DC source is constantly supplied via a resistor.
  • the flux in the core can be automatically cancelled when the current through the primary winding of the transformer vanishes, i.e. when the switching element is turned off, but the constant reset current flowing through the resistor into the reset winding gives rise to heat loss and therefore the problem of heat dissipation. For this reason the power source section cannot be made small in size. This makes unsuitable the provision of the power source in an electronic computer.
  • the conventional artifice of preventing damage due to the flyback voltage is to cramp the flyback voltage by a circuit consisting of a diode, a resistor and a capacitor so as to make the amplitude of the flyback voltage equal to that of the voltage of the power source so that the switching element may be prevented from being damaged.
  • a circuit consisting of a diode, a resistor and a capacitor so as to make the amplitude of the flyback voltage equal to that of the voltage of the power source so that the switching element may be prevented from being damaged.
  • current flows through the resistor of the cramping circuit to cause heat loss.
  • the main object of this invention is to provide a DC-to-DC converter in which heat loss in the power section is small and which has a high efficiency.
  • the notable features of this invention are as follows.
  • the current through the primary winding of the transformer vanishes, i.e. when the switching element is turned off, the current then flowing through the smoothing choke coil is caused to flow through a part of the secondary winding of the transformer, so that the level of the magnetic flux of the core of the transformer may be restored to its initial value.
  • the flyback voltage generated when the switching element is turned off is cramped to the level of the source voltage so that the switching element may be prevented from being damaged.
  • FIG. 1 is a circuit of a DC-to-DC converter according to one embodiment of this invention.
  • FIG. 2 shows waveforms useful to explain the operation of the circuit shown in FIG. 1.
  • FIGS. 3 and 4 are circuits of converters according to other embodiments of this invention.
  • FIG. 1 shows one embodiment of this invention, which comprises a DC source 1, a transformer 2 whose core exhibits a rectangular hysteresis characteristic and which includes a primary winding N 1 and a secondary winding consisting of N 2 , N 3 and N 4 , a switching transistor 3 connected in series with the primary winding N 1 and forming a closed circuit with the DC source 1 (E), a rectifying diode 4, a smoothing choke coil 5, a flywheel diode 6, a cramping diode 7, a smoothing capacitor 8, a load 9, a difference amplifier 10 to compare the output voltage E O with a reference voltage E r (11) and to obtain an amplified output, a drive pulse generator 12, and an insulating pulse transformer 13.
  • a DC voltage proportional to the voltage E of the source 1 can be supplied for the load 9 by switching the transistor 3. If a tap to separate the winding N 3 from the winding N 2 is so provided that the voltage across the winding N 3 may be negligible with respect to that across the winding N 2 , the flywheel diode 6 connected with the tap is not conductive while the transistor 3 is conductive. When the transistor 3 is cut off, the current flowing till then through the choke coil 5 starts circulating through a path consisting of the capacitor 8, the winding N 3 and the diode 6. This current through the winding N 3 (i.e. through the diode 6) serves to reset the level of the magnetic flux of the transformer core.
  • FIG. 2 shows waveforms appearing at several points in the circuit shown in FIG. 1 during the operation thereof.
  • Waveform (A) corresponds to the conductive and non-conductive states of the transistor 3
  • waveform (B) to the collector voltage of the transistor 3
  • waveform (C) to the current through the diode 4
  • waveform (D) to the current through the diode 6
  • waveform (E) to the current through the choke coil 5.
  • the level of the magnetic flux of the transformer core is restored to the initial value by diverting the current flowing till then through the choke coil 5 to the circuit of the winding N 3 and the diode 6.
  • the level + ⁇ m is reset to the level - ⁇ m . It is therefore unnecessary to supply a constant reset current so that the resultant heat loss can be rendered very small.
  • the loss in the conventional DC-to-DC converter is about 20 W while the corresponding loss in the DC-to-DC converter according to this invention is several watts.
  • a flyback voltage is generated by the winding N 4 when the transistor 3 is cut off.
  • the flyback voltage developed across the winding N 4 exceeds the output voltage E O , the diode 7 for cramping starts conduction, so that the flyback voltage is cramped to the level of the output voltage E O .
  • there is no heat loss owing to a resistor and a DC-to-DC converter having a high efficiency can be realized.
  • the duration of the pulse from the drive pulse generator 12 is controlled by the output of the difference amplifier 10. Consequently, the conductive time of the transistor 3 is controlled and the feedback control is performed to stabilize the output voltage E 0 .
  • FIG. 3 shows another embodiment of this invention, in which a second and a third auxiliary outputs are obtained and the flyback voltage is cramped to the level of the second auxiliary output E 2 .
  • Output windings N 5 and N 6 are provided in the transformer 2', the output of the winding N 5 being supplied through a diode 14 and a smoothing capacitor 15 for a load 16 and the output of the winding N 6 being fed through a diode 17 and a capacitor 18 to a load 19.
  • the polarity of the winding N 5 is opposite to those of the windings N 2 , N 3 and N 6 so that the flyback voltage generated when the transistor 3 is cut off is applied through the diode 14 to the smoothing capacitor 15.
  • the output voltage of the winding N 5 i.e. flyback voltage
  • the output voltage of the winding N 5 i.e. flyback voltage
  • FIG. 4 shows a third embodiment of this invention, in which the means for resetting the level of the magnetic flux of the transformer core is modified.
  • the transformer 2" has a primary winding N 1 and a secondary winding consisting of N 2 and N' 3 and the like ends (having the same polarity) of the windings N 2 and N' 3 are connected respectively through the diodes 4 and 6 with one end of the choke coil 5 while the other like ends of the windings N 2 and N' 3 are commonly connected via the smoothing capacitor 8 with the other end of the choke coil 5.
  • the capacitor 8 is shunted by the load 9 through which DC power is consumed.
  • the number of turns of the winding N' 3 is smaller than that of the winding N 2 .
  • the switching transistor when the switching transistor is cut off, the current flowing till then through the choke coil is in turn caused to flow through a part of the secondary winding of the transformer, so that the level of the magnetic flux of the transformer core may be restored to its initial value. Further, the flyback voltage generated when the switching transistor is turned off, is cramped to the level of the output voltage so that heat loss is small and the overall device, i.e. a DC-to-DC converter, having a smaller size can be realized. Namely, a reduction in size and cost of more than 20 percent can be expected according to this invention, as compared with the conventional DC-to-DC converter.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)
US05/388,260 1972-08-14 1973-08-14 DC-to-DC converter Expired - Lifetime US3935526A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JA47-80757 1972-08-14
JP47080757A JPS52204B2 (enrdf_load_stackoverflow) 1972-08-14 1972-08-14

Publications (1)

Publication Number Publication Date
US3935526A true US3935526A (en) 1976-01-27

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US05/388,260 Expired - Lifetime US3935526A (en) 1972-08-14 1973-08-14 DC-to-DC converter

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US (1) US3935526A (enrdf_load_stackoverflow)
JP (1) JPS52204B2 (enrdf_load_stackoverflow)

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4122514A (en) * 1976-11-01 1978-10-24 Hewlett-Packard Company Direct current power supply
US4135233A (en) * 1976-06-10 1979-01-16 Christian Rovsing A/S Voltage control circuit for a DC-to-DC convertor
US4245286A (en) * 1979-05-21 1981-01-13 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Buck/boost regulator
US4253137A (en) * 1977-03-11 1981-02-24 U.S. Philips Corporation Switched-mode power supply
WO1981002077A1 (en) * 1980-01-14 1981-07-23 Gen Electric Dc to dc voltage conversion apparatus
US4368419A (en) * 1979-06-13 1983-01-11 Branson International Plasma Corporation Power supply and method utilizing applied current for increased hysteresis swing in transformer core
US4481565A (en) * 1982-07-08 1984-11-06 Rca Corporation Core reset for single-ended dc-to-dc converter
EP0128988A1 (fr) * 1983-06-15 1984-12-27 Compagnie De Signaux Et D'equipements Electroniques Procédé et dispositif pour éliminer les perturbations liées aux fluctuations de la charge dans les alimentations à découpage
US4602323A (en) * 1984-11-05 1986-07-22 Burroughs Corporation Single-ended transformer drive circuit
GB2172155A (en) * 1985-03-01 1986-09-10 Thomson Brandt Gmbh Voltage converter
US4641229A (en) * 1981-03-18 1987-02-03 Rca Corporation Switching DC-to-DC converters
US4672517A (en) * 1985-05-28 1987-06-09 Pioneer Magnetics, Inc. Switched power supply of the forward converter type
US4680687A (en) * 1984-08-07 1987-07-14 Siemens Aktiengesellschaft Switch-mode power supply having a free-running forward converter
US4683528A (en) * 1985-07-22 1987-07-28 Intersil, Inc. Pulse position modulated regulation for power supplies
US4734839A (en) * 1987-03-23 1988-03-29 Barthold Fred O Source volt-ampere/load volt-ampere differential converter
US4745538A (en) * 1985-03-28 1988-05-17 Coutant Electronics Limited Electrical power supplies
US4835669A (en) * 1988-09-26 1989-05-30 Hughes Aircraft Company Dual mode flyback power supply
US4922397A (en) * 1988-02-16 1990-05-01 Digital Equipment Corporation Apparatus and method for a quasi-resonant DC to DC bridge converter
US5694304A (en) * 1995-02-03 1997-12-02 Ericsson Raynet Corporation High efficiency resonant switching converters
US6314003B2 (en) * 1998-08-20 2001-11-06 Infineon Technologies Ag Switched-mode power supply
US20080271777A1 (en) * 2005-12-30 2008-11-06 Paul Stoner Method and apparatus for eye-safe transmittal of electrical power in vehicles using white light via plastic optical fiber
WO2014149017A1 (ru) * 2013-03-18 2014-09-25 Klyosov Vladimir Alekseevich Источник питания системы электрического отопления

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS50129922A (enrdf_load_stackoverflow) * 1974-03-30 1975-10-14
JPS5287645A (en) * 1976-01-16 1977-07-21 Mitsubishi Electric Corp Electric power supply
JPS52102517A (en) * 1976-02-23 1977-08-27 Mitsubishi Electric Corp Power source equipment
JPS5321758A (en) * 1976-08-12 1978-02-28 Matsushita Electric Ind Co Ltd Power supply for converter

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2920259A (en) * 1956-01-27 1960-01-05 Philips Corp Direct current converter
US3331008A (en) * 1964-09-14 1967-07-11 Gen Electric Transformer coupled time ratio controlled circuits
US3629686A (en) * 1969-04-25 1971-12-21 Philips Corp Voltage supply apparatus for applying a direct current to a periodically varying load
US3740639A (en) * 1972-04-06 1973-06-19 Rca Corp Transformer coupled switching regulator
US3742371A (en) * 1971-12-16 1973-06-26 Tektronix Inc Wide range regulated power supply utilizing optimized energy storage

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2920259A (en) * 1956-01-27 1960-01-05 Philips Corp Direct current converter
US3331008A (en) * 1964-09-14 1967-07-11 Gen Electric Transformer coupled time ratio controlled circuits
US3629686A (en) * 1969-04-25 1971-12-21 Philips Corp Voltage supply apparatus for applying a direct current to a periodically varying load
US3742371A (en) * 1971-12-16 1973-06-26 Tektronix Inc Wide range regulated power supply utilizing optimized energy storage
US3740639A (en) * 1972-04-06 1973-06-19 Rca Corp Transformer coupled switching regulator

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4135233A (en) * 1976-06-10 1979-01-16 Christian Rovsing A/S Voltage control circuit for a DC-to-DC convertor
US4122514A (en) * 1976-11-01 1978-10-24 Hewlett-Packard Company Direct current power supply
US4253137A (en) * 1977-03-11 1981-02-24 U.S. Philips Corporation Switched-mode power supply
US4245286A (en) * 1979-05-21 1981-01-13 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Buck/boost regulator
US4368419A (en) * 1979-06-13 1983-01-11 Branson International Plasma Corporation Power supply and method utilizing applied current for increased hysteresis swing in transformer core
WO1981002077A1 (en) * 1980-01-14 1981-07-23 Gen Electric Dc to dc voltage conversion apparatus
US4313155A (en) * 1980-01-14 1982-01-26 General Electric Company High input voltage DC to DC power converter
US4641229A (en) * 1981-03-18 1987-02-03 Rca Corporation Switching DC-to-DC converters
US4481565A (en) * 1982-07-08 1984-11-06 Rca Corporation Core reset for single-ended dc-to-dc converter
EP0128988A1 (fr) * 1983-06-15 1984-12-27 Compagnie De Signaux Et D'equipements Electroniques Procédé et dispositif pour éliminer les perturbations liées aux fluctuations de la charge dans les alimentations à découpage
US4680687A (en) * 1984-08-07 1987-07-14 Siemens Aktiengesellschaft Switch-mode power supply having a free-running forward converter
US4602323A (en) * 1984-11-05 1986-07-22 Burroughs Corporation Single-ended transformer drive circuit
GB2172155B (en) * 1985-03-01 1989-06-28 Thomson Brandt Gmbh Voltage transformer
GB2172155A (en) * 1985-03-01 1986-09-10 Thomson Brandt Gmbh Voltage converter
US4745538A (en) * 1985-03-28 1988-05-17 Coutant Electronics Limited Electrical power supplies
US4672517A (en) * 1985-05-28 1987-06-09 Pioneer Magnetics, Inc. Switched power supply of the forward converter type
US4683528A (en) * 1985-07-22 1987-07-28 Intersil, Inc. Pulse position modulated regulation for power supplies
US4734839A (en) * 1987-03-23 1988-03-29 Barthold Fred O Source volt-ampere/load volt-ampere differential converter
US4922397A (en) * 1988-02-16 1990-05-01 Digital Equipment Corporation Apparatus and method for a quasi-resonant DC to DC bridge converter
US4835669A (en) * 1988-09-26 1989-05-30 Hughes Aircraft Company Dual mode flyback power supply
US5694304A (en) * 1995-02-03 1997-12-02 Ericsson Raynet Corporation High efficiency resonant switching converters
US6314003B2 (en) * 1998-08-20 2001-11-06 Infineon Technologies Ag Switched-mode power supply
US20080271777A1 (en) * 2005-12-30 2008-11-06 Paul Stoner Method and apparatus for eye-safe transmittal of electrical power in vehicles using white light via plastic optical fiber
US7968789B2 (en) * 2005-12-30 2011-06-28 International Optical Interface, Inc. Method and apparatus for eye-safe transmittal of electrical power in vehicles using white light via plastic optical fiber
WO2014149017A1 (ru) * 2013-03-18 2014-09-25 Klyosov Vladimir Alekseevich Источник питания системы электрического отопления
GB2527469A (en) * 2013-03-18 2015-12-23 Vladimir Alekseevich Klyosov Power supply source for an electric heating system

Also Published As

Publication number Publication date
JPS52204B2 (enrdf_load_stackoverflow) 1977-01-06
JPS4937122A (enrdf_load_stackoverflow) 1974-04-06

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